The present disclosure relates generally to electronic display devices and more specifically to controlling thermal spreading in electronic display devices.
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Organic light emitting diodes (OLEDs) are being increasingly employed for display applications in a wide variety of electronic devices, including such consumer electronics as televisions, computers, and handheld devices (e.g., cellular telephones, digital cameras, audio and video players, gaming systems, and so forth). Such OLED devices typically include a flat display panel having, among other things, an array of OLEDs that emit light to form an image. Each OLED includes one or more thin organic layers disposed between two charged electrodes (anode and cathode). The organic layers may include, for example, a hole injection layer, a hole transport layer, an emissive layer, an electron transport layer, and an electron injection layer. Upon application of an appropriate voltage to the OLED device, the injected positive and negative charges recombine in the emissive layer to produce light.
The luminance available from these organic layers generally degrades throughout the lifetime of the OLED. The lifetime of OLEDs used in electronic device displays may be affected by their temperature. For example, the OLED may work less efficiently at lower temperatures, requiring a slightly higher applied voltage to emit a desired amount of light, and OLED luminance generally degrades faster when the OLED is driven harder. Moreover, frequently used electronic components within an OLED device may produce excess heat, leading to high temperature concentrations in regions adjacent the OLED display. For example, a cellular phone user who engages in frequent telephone conversations may use the transmitter positioned near an upper region of the display, while a user who plays more video games may use the processor positioned near a lower region of the display. The OLEDs may degrade even faster in regions of the display exposed to these higher temperatures, resulting in non-uniform visual artifacts in the displayed image. In particular, white spots or image burn-in may result from temperature gradients within the display.